Users of plastics and elastomers generally have a wide range of polymer compositions from which to select to optimize product cost and performance. There are instances, however, where problems such as staining or plasticizer migration drastically reduce the number of options available. Plasticized polyvinyl chloride compositions are a well-known illustration of materials subject to such problems. Plasticized polyvinyl chloride (PVC) coatings are stained by many substances including cigarette smoke and cosmetics. When used in a confined space or in contact with other polymeric materials, the plasticizers in many polyvinyl chloride compositions may migrate or volatilize to cause a variety of problems. Barrier coatings or top coatings of other polymers have been used in an effort to overcome problems of the type just described for plasticized polyvinyl chloride. A number of copolyesters have been found useful as barrier coatings; however, they are far too stiff for use in situations where flexibility of the substrate is important.
A number of copolyetheresters have also been considered as barrier coatings but in general were found to be either too stiff for use with flexible substrates or lacking in barrier properties. The present invention is related to novel elastomeric copolyesters which are stain-resistant and relatively impervious toward plasticizers. They form top coats that are tough, adherent, transparent and flexible. The balance of properties that they possess provides advantages over conventional copolyesters or copolyetheresters.